Electret condenser microphones, which can be made compact, are suitable as tie-pin microphones or gooseneck microphones for conference rooms.
Some gooseneck microphones include circuit boards in the vicinity of the microphone units. The circuit boards are each equipped with electronic circuits, such as an impedance converter, a tone control circuit, and a balanced output circuit.
The gooseneck microphones including electronic circuits in the vicinity of the microphone units are resistant to noise caused by external electromagnetic waves, because of the short wires between the circuits.
Unfortunately, a case to accommodate a circuit board for a typical traditional gooseneck microphone cannot be readily made compact because of difficulty in providing a structure for fixing the circuit board to the case.
The circuit board in such a traditional compact gooseneck microphone is thus placed in the case directly or with a sponge for absorbing vibrations. In other words, the circuit board is not firmly fixed inside the case in the traditional compact gooseneck microphone.
In addition, the circuit board and the case in the traditional gooseneck microphone cannot be readily wired to each other and thus have poor electrical connection. The high impedance at the contact results in poor grounding of the circuit board in the traditional gooseneck microphone. Hence, the traditional gooseneck microphone is not completely resistant to noise caused by RF current and external noise.
Besides, the traditional gooseneck microphone, which includes the circuit board not firmly fixed to the case, has problems of low stability of the circuit board inside the case and low productivity.
In order to solve the problems, techniques are disclosed for reducing the noise caused by external electromagnetic waves in gooseneck microphones (for example, refer to Japanese Unexamined Patent Application Publication No. 2012-222774 (PTL 1)).
Unfortunately, the technique disclosed in PTL 1 is directed to the shielding of an output module and not an improvement in the fixation of the circuit board to the case for better electrical connection therebetween.